For the engine fuel control system and control method of unstable ingredient gas sourceTechnical field
The invention belongs to engine fuel control technology fields, more particularly, to a kind of hair for unstable ingredient gas sourceMotivation Fuel Control System and control method.
Background technique
Natural gas main component is CH4, is high-quality clean fuel, the natural gas of exploitation by refine purification mainly with CNG,LNG is that principal mode carries out storage utilization, is partially widely used in gas engine product.But in industrial circle, have veryMore special gas sources, main component is based on CH4 and contains some other gaseous impurity, such as oil field gas, rubbish landfill gas, natural pondGas etc..The characteristics of this kind of gas source is that gas component is unstable, and each area also differs greatly, and gas component is with environment temperatureChange and change, environment temperature is high under normal conditions, and CH4 concentration is high in gas source, and environment temperature is low, and CH4 concentration reduces.EngineUsing the gas source that gas component is stable, it can be easier to control the air-fuel ratio of combustion gas, power output is also relatively stable.If using non-steadyDetermine the gas source (gas source of gas component variation) of ingredient, current combustion control system is difficult to carry out effective air-fuel ratio control,It is unstable often to will lead to engine start difficulty, power；Therefore it needs often to be adjusted engine data or mixer.NumberAccording to or the adjustment of mixer need engine to carry out under shutdown status, adjustment process will affect the actual use of client, aIt will lead to user in other situation to stop production due to power-off, often bring economic loss to user.
Summary of the invention
It is intended to overcome above-mentioned the deficiencies in the prior art, first technical problem solved by the invention is to proposeA kind of engine fuel control system for unstable ingredient gas source, can do targetedly according to the different gas source of clientSelf adaptive control guarantees that the normal operation of engine and stablizing for power export.
As the same technical concept, second technical problem solved by the invention is to propose one kind for non-steadyDetermine the engine fuel control method of ingredient gas source.
The present invention solves technical solution used by above-mentioned first technical problem: one kind is for unstable ingredient gas sourceEngine fuel control system, including proportional mixer, engine electric-controlled unit, the crankshaft for monitoring engine speedSpeed probe enters the electronic throttle of mixed gas flow in the air inlet pipe, for monitoring the air inlet pipe for controllingThe air inlet temperature/pressure sensor of interior mixture temperature pressure and lambda sensor for monitoring oxygen concentration in the exhaust pipe；The crankshaft rotational speed sensor, the electronic throttle, the air inlet temperature/pressure sensor and the lambda sensor are and instituteState engine electric-controlled unit electrical connection；
Combustion gas bypass line is provided between the fuel gas inlet end of the proportional mixer and mixed gas outlet end, it is describedIt is provided with the fuel gas temperature pressure sensor for monitoring fuel gas temperature pressure on combustion gas bypass line and enters institute for controllingState the combustion gas by-passing valve of gas flow in combustion gas bypass line.
Further, the fuel gas temperature pressure sensor is located at the combustion gas bypass line of combustion gas by-passing valve upstreamOn.
The present invention solves technical solution used by above-mentioned second technical problem: one kind is for unstable ingredient gas sourceEngine fuel control method, based on the engine fuel control system for unstable ingredient gas source, the controlMethod processed includes:
S1, engine initialization calibration, prestore in the engine electric-controlled unit under gas component, different operating conditionsCombustion gas by-passing valve basis aperture k0 under benchmark air-fuel ratio λ 0 and different operating condition；Initial air-fuel ratio λ 2 under different operating conditions is carried outInitialization calibration；
S2, the engine operate normally, and the engine electric-controlled unit acquisition electronic throttle aperture, engine turnSpeed, oxygen concentration and intake air temperature pressure data, and the data of acquisition are analyzed and processed, obtain the practical sky under current workingCombustion is than λ 1；
The initial air-fuel ratio λ 2 of S3, the engine electric-controlled unit based on actual air-fuel ratio λ 1 and calibration under current workingDifference, the aperture of the combustion gas by-passing valve is adjusted by PID control to carry out air-fuel ratio closed-loop control；Simultaneously according to the combustionThe fuel gas temperature pressure signal of gas temperature and pressure transmitter transmission is modified the aperture of presently described combustion gas by-passing valve；
S4, until actual air-fuel ratio λ 1 and calibration initial air-fuel ratio λ 2 difference within the scope of predetermined deviation, stop adjustSave the aperture of the combustion gas by-passing valve.
Further, in the step S1, the step of initialization is demarcated is carried out to initial air-fuel ratio λ 2 and is specifically included:
S11, the engine initial launch close air-fuel ratio closed loop regulatory function；The engine electric-controlled unit acquisitionElectronic throttle aperture, engine speed, oxygen concentration and intake air temperature pressure data, and the data of acquisition are carried out at analysisReason obtains the actual air-fuel ratio λ 1 under current working；
S12, it runs under declared working condition, by manually adjusting the aperture of the proportional mixer come presetting practical air-fuelThan λ 1；Then according to the difference of actual air-fuel ratio λ 1 and benchmark air-fuel ratio λ 0 under different operating conditions, by manually to the combustion gasBy-passing valve basis aperture k0 carries out initialization calibration and obtains initial combustion gas by-passing valve basis aperture k1, until the reality under different operating conditionsBorder air-fuel ratio λ 1 is with the difference of corresponding benchmark air-fuel ratio λ 0 within the scope of predetermined deviation；
S13, in the initialization calibration process of the initial combustion gas by-passing valve basis aperture k1, according to the practical fortune of engineMarket condition obtains initial air-fuel ratio λ 2 by carrying out initialization calibration to benchmark air-fuel ratio λ 0 manually；After the completion of calibration, open emptyCombustion verifies nominal data than closed loop regulatory function；
S14, by under the initial combustion gas by-passing valve basis aperture k1 and different operating condition under the different operating conditions of re-calibration justBeginning air-fuel ratio λ 2 is stored.
Further, in the step S3, according to the fuel gas temperature pressure signal of fuel gas temperature pressure sensor transmissionThe step of being modified to the aperture of the combustion gas by-passing valve specifically includes:
S31, the engine electric-controlled unit are based on the fuel gas temperature actual value Ta and fuel gas temperature preset value acquired in real timeThe difference of Td, regulating gas temperature coefficient Ft；
S32, the engine electric-controlled unit are based on the gaseous-pressure actual value Pa and gaseous-pressure preset value acquired in real timeThe difference of Pd, regulating gas pressure coefficient Fp；
The aperture of combustion gas by-passing valve=current gas by-passing valve aperture × (1+Ft+Fp) after S33, amendment.
Further, in the step S3, according to the fuel gas temperature pressure signal of fuel gas temperature pressure sensor transmissionThe step of being modified to the aperture of the combustion gas by-passing valve is specific further include:
S30, preset temperature correct constant α and pressure correction constant β.
Further, fuel gas temperature coefficient Ft=(Ta-Td) × α；
Gaseous-pressure coefficient Fp=(Pd-Pa) × β.
Further, in the step S3, according to the fuel gas temperature pressure signal of fuel gas temperature pressure sensor transmissionThe step of being modified to the aperture of the combustion gas by-passing valve is specific further include:
S310, when the fuel gas temperature actual value Ta be more than or equal to preset maximum temperature limit value Tmax when, trigger combustion gasThe alarm of temperature height；When the fuel gas temperature actual value Ta is less than or equal to preset minimum temperature limit value Tmin, combustion gas temperature is triggeredSpend low alarm；
S320, when the gaseous-pressure actual value Pa be more than or equal to preset maximum pressure limit value Pmax when, trigger combustion gasThe alarm of pressure height；When the gaseous-pressure actual value Pa is less than or equal to preset minimum pressure Pmin, triggering gaseous-pressure is lowAlarm.
Further, the gas component includes mean calorie gas component, maximum calorific value gas component and minimum calorific value combustionGas ingredient.
After above-mentioned technical proposal, the beneficial effects of the present invention are:
The present invention is directed to the engine fuel control system of unstable ingredient gas source, including proportional mixer, engineElectronic control unit, the crankshaft rotational speed sensor being electrically connected with engine electric-controlled unit, electronic throttle, air inlet temperature/pressure sensorAnd lambda sensor；It is provided with combustion gas bypass line between the fuel gas inlet end of proportional mixer and mixed gas outlet end, firesFuel gas temperature pressure sensor and combustion gas by-passing valve are provided on gas bypass line.Control method includes: S1, engine initializationCalibration, carries out initialization calibration to the initial air-fuel ratio λ 2 under different operating conditions；S2, engine operate normally, engine electric-controlled listMember obtains the actual air-fuel ratio λ 1 under current working；S3, engine electric-controlled unit are based on the actual air-fuel ratio λ 1 under current workingWith the difference of the initial air-fuel ratio λ 2 of calibration, air-fuel ratio closed loop control is carried out by the aperture of PID control regulating gas by-passing valveSystem；It is carried out simultaneously according to aperture of the fuel gas temperature pressure signal of fuel gas temperature pressure sensor transmission to current gas by-passing valveAmendment；Until the difference of actual air-fuel ratio λ 1 and the initial air-fuel ratio λ 2 of calibration within the scope of predetermined deviation, stop regulating gasThe aperture of by-passing valve.
The present invention can be different according to client by above-mentioned control system and the control method based on control system gas sourceTargetedly self adaptive control is done, the aperture of combustion gas by-passing valve can be accurately controlled according to gas component, is had to air-fuel ratioEffect control guarantees that the normal operation of engine and stablizing for power export.Without unstable because of gas component, and startingMachine carries out the adjustment of data or mixer under shutdown status, therefore not will lead to user and stopped production due to power-off, ensure thatThe economic benefit of user.
Detailed description of the invention
Fig. 1 is plane figure of the present invention for the engine fuel control system of unstable ingredient gas source；
Fig. 2 is control principle drawing of the present invention for the engine fuel control system of unstable ingredient gas source；
Fig. 3 is flow chart of the present invention for the engine fuel control method of unstable ingredient gas source；
Fig. 4 is the flow chart that initial air-fuel ratio λ 2 carries out initialization demarcating steps in Fig. 3；
Fig. 5 is according to the fuel gas temperature pressure signal of fuel gas temperature pressure sensor transmission in Fig. 3 to combustion gas by-passing valveThe step flow chart that aperture is modified；
In figure: 1- proportional mixer, 2- engine electric-controlled unit, 3- crankshaft rotational speed sensor, 4- electronic throttle, 5-Air inlet temperature/pressure sensor, 6- lambda sensor, 7- combustion gas bypass line, 8- fuel gas temperature pressure sensor, 9- combustion gas bypassValve, 10- combustion gas, 11- air inlet pipe, 12- exhaust pipe, 13- turbine.
Specific embodiment
In order to make the objectives, technical solutions, and advantages of the present invention clearer, with reference to the accompanying drawings and embodiments, rightThe present invention is further elaborated.It is retouched it should be appreciated that specific embodiment described herein is intended merely to facilitate simplificationIt states, to explain the present invention, is not intended to limit the present invention.
As Fig. 1 and Fig. 2 jointly shown in, for the engine fuel control system of unstable ingredient gas source, including proportion expressionMixer 1, the crankshaft rotational speed sensor 3 for monitoring engine speed, is used to control into air inlet engine electric-controlled unit 2The electronic throttle 4 of mixed gas flow, the intake air temperature pressure for monitoring mixture temperature pressure in air inlet pipe 11 in pipe 11Sensor 5 and lambda sensor 6 for monitoring oxygen concentration in 5 exhaust pipes 12；Crankshaft rotational speed sensor 3, electronic throttle 4,Air inlet temperature/pressure sensor 5 and lambda sensor 6 are electrically connected with engine electric-controlled unit 2；In addition to this, proportional mixerIt is provided with combustion gas bypass line 7 between 1 fuel gas inlet end and mixed gas outlet end, is provided with and is used on combustion gas bypass line 7It monitors the fuel gas temperature pressure sensor 8 of fuel gas temperature pressure and enters gas flow in combustion gas bypass line 7 for controllingCombustion gas by-passing valve 9.Ingredient into combustion gas 10 in proportional mixer 1 is unstable, belongs to unstable ingredient gas source.
In the present embodiment, air inlet temperature/pressure sensor 5 is located in the air inlet pipe 11 in 4 downstream of electronic throttle, oxygen sensingDevice 6 is set on the exhaust pipe 12 in 13 outlet end downstream of turbine；Fuel gas temperature pressure sensor 8 is located at combustion gas bypass line 7Upstream；Ensure the accuracy of monitoring data by reasonable Arrangement sensor.
The present embodiment also discloses a kind of based on the above-mentioned engine fuel control system for unstable ingredient gas sourceControl method.As Fig. 1, Fig. 3 to Fig. 5 jointly shown in, the core procedure of the control method includes:
S1, engine initialization calibration, gas component is prestored in engine electric-controlled unit 2, and (gas component includes averageCalorific value fuel gas ingredient, maximum calorific value gas component and minimum calorific value gas component), (λ 0 is real by benchmark air-fuel ratio λ 0 under different operating conditionsBorder represents the MAP chart table for inquiring air-fuel ratio) and different operating condition under combustion gas by-passing valve basis aperture k0 (the practical representative confession of k0 is looked intoAsk the MAP chart table of combustion gas by-passing valve basis aperture)；Initialization calibration is carried out to the initial air-fuel ratio λ 2 under different operating conditions.
It should be noted that combustion gas by-passing valve basis under benchmark air-fuel ratio λ 0 and different operating condition under the different operating conditions prestoredAperture k0 be it is tentative based on experience value, not fully correctly, it is therefore desirable to carry out initialization calibration；That is, in the base of empirical valueIt is re-scaled on plinth.
S2, engine operate normally, and engine electric-controlled unit 2 is passed by electronic throttle 4, crankshaft rotational speed sensor 3, oxygenSensor 6 and admission pressure temperature sensor 5；Acquire electronic throttle aperture, engine speed, oxygen concentration and intake air temperature pressureData, and the data of acquisition are analyzed and processed, obtain the actual air-fuel ratio λ 1 under current working.
The initial air-fuel ratio λ 2 of S3, engine electric-controlled unit 2 based on actual air-fuel ratio λ 1 and calibration under current workingDifference carries out air-fuel ratio closed-loop control by the aperture of PID control regulating gas by-passing valve 9；Simultaneously according to fuel gas temperature pressureThe fuel gas temperature pressure signal that force snesor 8 transmits is modified the aperture of current gas by-passing valve 9.
That is, the principle of PID control are as follows: if the initial air-fuel ratio λ 2 of calibration is greater than the actual air-fuel ratio λ 1 under current working,Illustrate that CH4 concentration becomes larger in combustion gas 10, the aperture that engine electric-controlled unit 2 controls to adjust combustion gas by-passing valve 9 reduces, and makes to enter hairThe gas quantity of motivation reduces, while the size of aperture can be modified that (ingredient of combustion gas 10 is by temperature, pressure according to temperature, pressureIt influences to increase, it is therefore desirable to correct)；If the initial air-fuel ratio λ 2 of calibration is less than the actual air-fuel ratio λ 1 under current working, explanationCH4 concentration becomes smaller in combustion gas 10, and the aperture that engine electric-controlled unit 2 controls to adjust combustion gas by-passing valve 9 increases, and makes to enter engineGas quantity increase, while the size of aperture can be modified according to temperature, pressure.PID control is that those skilled in the art are used toTechnological means is not described in detail herein.
S4, until actual air-fuel ratio λ 1 and calibration initial air-fuel ratio λ 2 difference within the scope of predetermined deviation, stop adjustThe aperture of gas fuel saving by-passing valve 9.
In the present embodiment, the step of initialization is demarcated is carried out to initial air-fuel ratio λ 2 and is specifically included:
S11, engine initial launch close air-fuel ratio closed loop regulatory function；Lambda sensor 6 is not needed at this time to engineElectronic control unit 2 provides feedback signal, is served only for monitoring oxygen concentration i.e. actual air-fuel ratio；Engine electric-controlled unit 2 passes through electronics sectionValve 4, crankshaft rotational speed sensor 3, lambda sensor 6 and admission pressure temperature sensor 5, acquisition electronic throttle aperture are startedMachine revolving speed, oxygen concentration and intake air temperature pressure data, and the data of acquisition are analyzed and processed, obtain the reality under current workingBorder air-fuel ratio λ 1；Do not start to be demarcated at this time, that is, wouldn't be carried out under the operation of engine idling condition, partial load conditionCalibration.
S12, it runs under declared working condition, by manually adjusting the aperture of proportional mixer 1 come presetting actual air-fuel ratio λ1 (λ 1≤λ of 0-c≤λ 0+c, c are fixed value；Primary, subsequent operating condition no longer comparative example formula mixer 1 is only lowered in declared working conditionIt is adjusted)；Then according to the difference of actual air-fuel ratio λ 1 and benchmark air-fuel ratio λ 0 under different operating conditions, by (manual manuallyRefer to and set basic opening value in engine electric-controlled unit 2 again, original basis aperture k0 is replaced) to combustion gas by-passing valveBasic aperture k0 carries out initialization calibration acquisition initial combustion gas by-passing valve basis aperture k1, and (k1 is practical to be represented for inquiry initialization markThe MAP chart table of combustion gas by-passing valve basis aperture after fixed), until actual air-fuel ratio λ 1 under different operating conditions and corresponding benchmarkThe difference of air-fuel ratio λ 0 is within the scope of predetermined deviation.
S13, in the initialization calibration process of initial combustion gas by-passing valve basis aperture k1, according to engine actual motion feelingsCondition by (referring to set air fuel ratio value in engine electric-controlled unit 2 again manually, the quasi- air-fuel ratio λ 0 of former base is replaced manuallyChange) the initial air-fuel ratio λ 2 of initialization calibration acquisition is carried out to benchmark air-fuel ratio λ 0；After the completion of calibration, opens air-fuel ratio closed loop and adjustFunction verifies nominal data.
In engine actual motion, the aperture of calibration adjustment combustion gas by-passing valve 9 anyway, benchmark air-fuel ratio λ 0 can be encounteredWith the difference of actual air-fuel ratio λ 1 still can not within the scope of predetermined deviation situation or engine can not work normally and (send outMotivation rotary speed unstabilization, power swing)；Illustrate that the benchmark air-fuel ratio λ 0 for being worth setting by rule of thumb is inappropriate at this time, it is therefore desirable to itIt is re-scaled.
S14, by under the initial combustion gas by-passing valve basis aperture k1 and different operating condition under the different operating conditions of re-calibration justBeginning air-fuel ratio λ 2 is stored.Lookup after operating normally convenient for engine is called.
In short, initialization calibration process be modified on the basis of experience preset value it is perfect.Make its subsequent skyThe control for firing ratio is more accurate.
In the present embodiment, in step S3, the fuel gas temperature pressure signal transmitted according to fuel gas temperature pressure sensor 8 is to combustionThe step of aperture of gas by-passing valve 9 is modified specifically includes:
S30, preset temperature corrects constant α and pressure correction constant β in engine electric-controlled unit 2.
S31, engine electric-controlled unit 2 are based on fuel gas temperature actual value Ta (the fuel gas temperature pressure sensor 8 acquired in real timeReal-time monitoring) and fuel gas temperature preset value Td difference, regulating gas temperature coefficient Ft；Fuel gas temperature coefficient Ft=(Ta-Td)×α.That is, as Ta > Td, Ft increases, and when Ta < Td, Ft reduces.
S310, when fuel gas temperature actual value Ta be more than or equal to preset maximum temperature limit value Tmax when, trigger fuel gas temperatureHeight alarm；When fuel gas temperature actual value Ta is less than or equal to preset minimum temperature limit value Tmin, the low alarm of triggering fuel gas temperature.
S32, engine electric-controlled unit 2 are based on gaseous-pressure actual value Pa (the fuel gas temperature pressure sensor 8 acquired in real timeReal-time monitoring) and gaseous-pressure preset value Pd difference, regulating gas pressure coefficient Fp；Gaseous-pressure coefficient Fp=(Pd-Pa)×β.That is, as Pa > Pd, Fp reduces, and when Pa < Pd, Fp increases.
S320, when gaseous-pressure actual value Pa be more than or equal to preset maximum pressure limit value Pmax when, trigger gaseous-pressureHeight alarm；When gaseous-pressure actual value Pa is less than or equal to preset minimum pressure Pmin, the low alarm of triggering gaseous-pressure.
The aperture of combustion gas by-passing valve=current gas by-passing valve aperture × (1+Ft+Fp) after S33, amendment；In the formulaThe aperture of current gas by-passing valve be aperture after air-fuel ratio closed-loop control.
The present invention can be different according to client by above-mentioned control system and the control method based on control system gas sourceTargetedly self adaptive control is done, the aperture of combustion gas by-passing valve can be accurately controlled according to gas component, is had to air-fuel ratioEffect control guarantees that the normal operation of engine and stablizing for power export.Without unstable because of gas component, and startingMachine carries out the adjustment of data or mixer under shutdown status, therefore not will lead to user and stopped production due to power-off, ensure thatThe economic benefit of user.
The above is presently preferred embodiments of the present invention, is not intended to limit the invention, all in spirit of the inventionWith any modification and improvement made within principle, protection scope of the present invention should be included in.